Engine starting mechanism



Oct. 31, 1933. y R M, NARDONE 1,933,534

ENGINE STARTING MECHANISM Filed Aug. 3, 1931 V fM TTo'RNEY jferred to. f

4Another object of theinvention is to'provideA Patented Qct. 31, 1933nfsTATgs! was@ A 1,953,534f` y l l y ENGINEV'SVTART'ING MECHANISM` RomeoM. Nardone, Orange, N. J., assigner to Eclipse Aviation-f Corporation,East` Orange,

N. J., a corporation of New Jersey Aspiration Agust 3, 193i. serial N0.-554373 o 10 Claims.

This invention relates to engine starting mechanisms and particularly tothose adapted to impartuthe initial turning force to a member, such asthe crankshaft,y .of an engine having other g means for maintainingitself in operation after such initial turning or cranking.Y f f Anobject ofthe invention is to provide a starter for the foregoing purposeembodying novel'means for 'establishing driving connectionbetweenarotatable element ofthestarter and a rotatable member `of the/engine,'which meansfinoludes yieldable means normally adaptedto maintainpositive driving connection between.. the. driving memberV of thestarter and the aforesaid rotatable j member, but adapted to yieldtemporarily to alo-- sorb'the sudden reverse f-torque resulting intheevent of a backfire of the engine to be started.

`v.ifurther object of the invention is to provide yieldable means of theforegoing character, ycon-A j structed and disposed in respeotto thedriving and driven elements of the starter, in such'm'anner asto beerlective to maintain positive driving relation between the saidelements even during. the assimilation of thereverset'orqueabove re-'iin a starterof thetype employing a member 'move ablelongitudinallyinto.engagement with a meni= ber of` the engine `to bestarted and thereafter rotatable to crank the engine'novelfmeans for.rotating said'rst named member at relatively.-

highspeed following completion ofits longitudinal movement. f

Another object vof th'e'inv'ention is to provide a j simple but emcientstarter for theioregoing purposes, which 'is' further. characterized bya novel arrangement of the. torque transmitting mechanism rendering the,starter suitable-"forv installation in engines `where. space isrestricted and j economy in size and weight is essential.

These and other objects andadvantages tobe derived from the use of theinvention disclosed herein will become evident on an inspection of thefollowingv description when read withvreferv ence to the4 accompanying.1drawing illustrating one embodiment of the invention. It is tobe,expressly understood, however, that thedrawing.

is for the purpose of illustration only,and is not to be construed as adefinition "of the limits of the invention, reference, beingl had forthis purpose to the appended claims.`

In the drawing,

Fig. 1 is a view in elevation withpartsl sl'lo'wn inelongitudinalsection ofthe device embodying the invention. l f

(CLIM-7) `Fig. 2 is a transverse section view 2-2 of Fig. 1;y and .v c

Fig. 3 is a view in elevation with parts broken away and others inysection of a portion` or" the assembly shown' in Fig. 1. l

Referring to the Adrawing and particularly to Fig. 1, the invention isshown embodiedin a along the line rstarter having a casing 'composed ofthree sections, 4, 5, and 6,-.the latter constitutingthe casingv for theprime mover, herein shown as :an electric 65 motor V'adapted to actuatean engine-engaging member ysupported within the iirst section 4fof thecasing and drivably connected to the prime mover throughl reductionmechanisms mounted `within 'the 'casing section 5, the three sectionsbeing 7o; l

of considerably larger diameter and rotatableon a sleevefbearing 18about ashaft 21 Whose.` axis preferably is in alignment with that `ofthe85, rotatable member of the engine with which "they starter isadapted to `be drivably connected. As shown,Y the f casing `section 5is` provided 'with a suitablel thickened v.portion or hub 123 forming asupport in v,which the shaft` 2lis held against 90v yendwise movement ineitherdirection by y'previa sionoiav shoulder 19 and'a'retaining disc22, while `the gear 20 is providedwith a forwardlyextended hub 24 onwhich are'iormed teeth `2,5,

constituting a `'pin-ion adapted to drive the plane#l 95 tary gears26,.each of which meshes with a stationary annulus gear 49and rotatableabout 'a pin 27 on the `forwardv rend of each of which-is threaded a nut28 adapted to retain the o operative relation with a flange 29iorn1ed'on100 `a hollow-driving member or barrel 'qrotatably supported withinthehun-'9 of the casing section 4, the annulus gear `49 being -heldagainst"rota-V ftionbybolts 'l'. The barrel 30 .is-in turn' drivablyconnected to an internallythreaded sleeve 105 31 by novel meansconstitutingfoneofftheinajor features lof the invention now to `bedescribed. f The' novel means for eiiectinga nornf'ially.posi-fVytive-"c irivefrom' the barrel Sil-"to the sleeve'lgfwhile at the sametime absorbing shockincijdent 110 to a sudden application of torque inthe reverse direction, preferably takes the form of a pin and slotconnection between these members, such a pin being indicated at 32 ashaving a head portion movable along a diagonally directed slot oropening 33 in the wall of the barrel 30, while the shank portion of thepin 32 is threaded or otherwisepermanently secured to an intermediate`sleeve member 34 interposed between the barrel and threaded sleeve 31and preferably provided with a portion 35 of smaller external diameterbut of the same internal diameter, such construction providing anannular recess between the members 35 and 30 in which is placed a coilspring 36 normally stressed suf.-

'ciently to maintain the pin 32 in the position indicated in Fig. 3 inwhich position the drive, under normal torque conditions, from thebarrel 30 to the member 34 is positive and direct. Similar directconnection is provided between the member 34 and the sleeve 31 byforming external splines 37 on the latter member, adapted to registerwith corresponding longitudinal extensions 38 on the member 34, thelength of such extension 38 being such as Ato allow a predeterminedlongitudinal movement thereof in the event of suddenly applied torquetending to rotate the parts in a reverse direction, the amount ofpermissible longitudinal movement being preferably equal to the lengthof the slot 33 as projected along the axis of the members. Theinternally formed threads on the sleeve 31 are adapted to registerloosely with corresponding externally formed threads 39 on theengine-engaging member 40 which is provided at its outer end withradially disposed teeth 41 adapted to engage the corresponding teeth ofa jaw 42 secured to or as shown, integral with a rotatable member of theengine. kIn order to enforce lon-- gitudinal movement of the -member 40to mesh jaws 41 and 42, and in order to insure proper mesh of thesemembers, detent iingers 44 are provided to engage the smooth cylindricalsurface of the member 40 withia frictional pressure suicient to preventrotation of the member 40 during the period of its longitudinal advanceinto engagement withr the engine member, such longitudinal advance beingproduced in response to the rst rotation of the sleeve 31 followingenergization of the prime mover. Suitable `means, such as indicatedat'46, maybe employed for retaining the friction elements 44 infrictionexerting relation to the member 40. Inv the drawing, only one ofthe friction elements is shown, but it will be understood that othersmay be provided at suitable intervals about the ange 47, the latter alsobeing provided with apertures 48 for the reception of means forattachment of the starter to the crankcase, or other supportingstructure of the engine to be started.

In operation, energization of the motor 6 will rvbe transmitted atreduced speed to the barrel 30 mediately with said sleeve, and willtherefore be constrained by the turningof said sleeve and by thefrictional pressure of the detent fingers 44, to move ,forward withoutany rotary movement until the teeth 4l have meshed with those lof theengine member. isY the shaft is thus advanced, stop nut 50 is carriedalong, and after meshing begins, will contact with the shoulder 51 inwhich the threaded portion of the sleeve 31 terminates. Thereafterfurther longitudinal movement of the shaft 40 being impossible thelatter member will rotate with the sleeve 31 and thus impart suflicienttorque to the engine-member to allow the engine to develop sufcientcompression for starting under its own power.

In the event the engine backfires during the cranking operation, ayreverse torque is transmitted from the jaw teeth through the threadedconnection to the sleeve 34, causing thepin 32 to slide along theinclined slot 33, thus moving the sleeve 34 to the left as viewed inFigs. 1 and 3 and compressing the spring 36. During this compressingaction, limited and predetermined torque is transmitted through thegears to the armature of the motor, thereby rst retarding it and finallybringing it to a stop. At'the same time, a greater degree of torque isapplied to the engine to stop further backward rotation thereof. Ifequilibrium is not established before the pin reaches the end of theslot 33, the engine drives the armature shaft in a reverse directionuntil the energy caused by the backre has been dissipated. On the otherhand, if equilibrium is established before the pin reaches theend Vofthe slot 33, spring 36 will be effective to return pin 32 and member 34to the normal position as shown in Figs. 1 and 3, therebyre-establishing direct cranking Aoperation ybetween the prime mover andthe engine. In either of these events, it will be seen that the shockproduced by the engine backfire has been assimilated by the yieldingconnection and without any possibility of serious injury to the parts ofthe starter, such as the gearing or motor.

After the engine has started under its own power, the inclination of thejaw teeth will cause the return of the shaft 40 back to the disconnectedposition, in which position it will remain until the next operation ofthe starter.

There is thus disclosed a novel engine starter of the inertia type whichis simple and rugged in structure, inexpensive to manufacture andeicient in operation. It is especially adapted for use with smallengines because of its compactness and light weight, but since it is aselfcontained unit, it may be easily attached to any engine, andrequires no external supporting means other than a mounting flange orbracket provided on the engine housing.-

Whilel the embodiment above'udescribed possesses considerable practicalmerit, the invention is not limited to such embodiment since the novelprinciples may be incorporated in structures varying considerably fromthat above described. Thus, for example, a cam and follower`construction may be substituted for the pin and slot connection shownatf32 and 33 in the accompanying drawing, and other types of yieldingmeans may be employed in place of the coil springs 36. Moreover, incases where the requirements permit, the motor maybe mounted incoaxial-alignment with l the engine-engaging member and other types ofgearing substituted for that shown'.

VIt is to be understood that varfous otherv changes may be made in theform, details of construction and arrangement of the parts and the usesto which they are applied, without departing 'from the spirit of theinvention or the scope of the appended claims.

, means comprising a pair of concentr-ically dis.

1i. .Inan engine:startingrnechanism .of theftype employing'poweroperated driving means-and 1a driven member :engageable Withfa `.memberoi, 'the engine to be startedwthe combination with i said vdriven memberinto engine engagingxpositlon and` maintaining it innsaid `positionregardlessl or rany angular displacement of said .driving connection.`

In an engine starting mechs'inism off-.the type employing power operated,driving means.. anda driven member ,.engageable with. a member ofctheengine .to be started; the,combinationwithsaid driving lrneans; rdrivenfmember" andr engine member ofA a means -for.yieldably retarding.ther'otary speedoisaid driving means andethereat'er ref versingy thedirection; o rotation. of 1 said. driving means in the event of a suddenreversal ofthe directonfoi.rotationoflthe engine member during itsengagementwith said driven member,` said posed sleeves, one of which isslotted oblquely of their common axisr of rotation, and means-projecting from the other of said sleeves for engagement with theslotted portion of said first named sleeve to be driven thereby, andmeans distinct from both said sleeves for shifting said driven memberinto engine engaging position.

3'. In anengine starting mechanism of the type employing power operateddriving means and a driven memberengageable with a member of the engineto be started, the combination with said driving means, driven memberand engine mem# ber or a sleeve drivably connected to said -drivenmember, a second sleeve slotted obliquely of its common axis anddrivably connected to saiddriving means, 'and means projectng from saidrst vnamed sleeve for engagement with the slotted portion of said secondsleeve to be driven thereby, and means for yieldably preventing relativerotatio-nbetween said projecting means and said second sleeve, and meansdistinct from both said sleeves for shifting said driven member intoengine' engaging position. Y

4. In an engine starting mechanism of the type employing vpower operateddriving means and a driven member engageable with a member of the engineto be started, the combination with said driving means, driven memberand engine member of means comprising a pair of con- 'centricallydisposed sleeves normally rotatable in unison but capable of limitedrelative rotation in the event of reversal of the direction of torquetransmission, anda third sleeve splined to one of said iirst namedsleeves and threadedly engaging said ribbon member. l

' 5. In an engine starting mechanism of the type employing poweroperated driving means and a driven member engageable with a member ofthe engine to be started, the combination with said driving means,driven member and engine member of a sleeve interposed between saiddriving meansand driven member, said sleeve having a v screw threadeddriving connection with said driven member and means for yieldablyretarding ,disposed units. f Y l l 6.: In ani enginestarting imechanismof l.the type-,employing` power operated driving. means thelrotar-yspeedioisaididrvng.means andthereafterfreversingthe direction ofrotationofy said driving.' means' in the. event of a sudden `reversalA .of theydirection of rotation of `the enginemember during its 'engagement withsaiddriven member,zs`aid means ycomprising a pair .ofconcentrioallydisposed members surrounding said threaded'slceve andnormally rotatable 1in unison but capable fof limited`r relativerotation in the eventv of reversal or" the direction .of torque"transmise sion,:.said screw threaded drivingv connectionbeing eiective`.to maintain said` drivenmember: in .engagement with said-engine memberduring- .the entire cranking process `regardless of'any change in therelative positionsy of said .and adriven member .engageable withxa.member of the engine to be started, the combination with saidxdrfivingi means,- driven `member Vand engine member of asleevefthreadedly engaging :said

driven member, and means ior [causing a revert y sal. of the directionof rotation of ysaid.,driving means in they event of a' suddenreversalv`of the direction of; rotation ofA the engine.. member? dur:

ing .itsl `engagement with .said-'driven member, and means fordelayingsnch reversal of ,rotation until: `absorption4oi.a;.predetermined amount of torque Y"generated in said kenginemember, saidy vversal of the direction of torque transmission,

concentrically L' and means constituted'by said. threadedv sleeve nformaintaining said driven'member in engagement with thel engine memberduring the entire cranking process regardless of anyrelative rotationWhiohmight occur between said concen' trically disposed members. v

'7. In an engine starting. mechanismA of the type employing poweroperated drivingfmeans k and a driven member engageable with a `member.

of the engine to be started, the combination with said driving means,`driven rmember and engine of concentrically disposed sleeves,'one ofwhich 'has splined engagement with said rst named sleeve and the otherof whichiis provided with inclined surfaces, and a member engageablewith one portion of said. `inclined surfaces during transmission oftorque in one direction and with another portion of said surfaces duringtransmission of torque in theA opposite direction.

8. In an enginey starting mechanism of `the type employing poweroperateddriving means and a driven member engageable with a mem-.y

ber of the engine toube started, the combination with said drivingmeans,drive n member and engine member of a sleeve'threadedly engagingsaid driven member, and means for yieldablyretarding the rotary speed ofsaid driving means and ythereafter reversing thedirection of rotation ofsaid driving means in the event of a sudden reversal of the direction ofrotation of the engine member and without producing any correspondingdisengaging movement on the part of said driven member during itsengagement with said driven member, said means comprising a pair ofconcentrically disposed sleeves, one of which has driving engagementwith said rst named sleeve and the other of which is provided withinclined surfaces and a member engageable with one vportion of saidinclined surfacesdurmg transmission of torque in one directionand withanother portion of said surfaces during torque transmission in theopposite direction.

9. In an engine starting mechanism of the type employing power operateddriving means and a driven member engageable with a member of the engineto be started, said driven memberhaving a threaded portion, thecombination with said driving means, driven member and engine member ofa means for causing a reversal of the direction of rotation of saiddriving means in the event of a. sudden reversal of the direction f ofrotation of the engine member during its engagement with said drivenmember, and means for delaying such reversal of rotation untilabsorption of a Lpredetermined amount of torque generated'in said enginemember, said means comprising a pair of concentrically disposed sleevesone of which is threaded internally to engage the correspondinglythreaded portion of said engine engaging member and the other of whichis provided with inclined surfaces, and a radially disposed pinengageable with one portion of said inclined surfaces duringtransmission of torque in one direction and with another portion of saidsurfaces during torque transmission in the opposite direction, saidradially disposed pin constituting the torque transmitting connectionbetween said driving means and threaded sleeve, said threaded sleeve anddriven member remaining axiallyxed during the en'- tire cranking periodregardless of any movement of said pin along said inclined surfaces.

l0. In a device of the class described, a driving member, a drivenmember, and a two-way driving connection between said members, saidAconnection comprising a radially disposed pin positively 'connecting'said driving and driven members and also adapted toppositively: connectsaid members for reversetorque transmission after a limited' degree ofrelative rotation between said pin and driving member, said drivenmember remaining in fixed axial position during the entire crankingperiod regardless of any relative rotation between said pin and drivingmember.

' ROMEO M. NARDONE.

